I am engaged in construction in Datang

"Sister Li Yin is not an ordinary woman." Empress Changsun smiled sweetly, her eyes gentle: "Sister-in-law has a daughter as old as you."

The stepsister is only one year younger than Changle, but she is always jumping around and lively like a little boy, while Changle has inherited her illness and is quiet every day.

Li Yin knew who Empress Changsun was talking about: "It must be someone like my sister-in-law, stunningly beautiful and naturally beautiful."

"Ah!" Empress Chang Sun covered her mouth and laughed happily, probably because she felt that Li Yin's praise was in line with Li Lizhi's name.

The three of them soaked in the water for quarter of an hour and then got up and left.

After everyone changed their clothes, it was time for dinner.

There was no time to cook in the village today, so we ate hotpot. We fried the base ourselves, with all kinds of flavors. We all gathered around the same stove and ate.

"This is a novel way to eat it." Empress Changsun said. On their table was a shabu-shabu pot, with clear soup on one side and tomatoes on the other. (There is no chili pepper yet, so if you like spicy food, add some dogwood and pepper.)

Li Yin was taking Empress Changsun's pulse while Li Shimin looked nervous. His sister-in-law was an excellent doctor and gave her many prescriptions that the Imperial Medical Bureau also wanted to study.

"It's nothing serious." Li Yin relaxed her brows: "With my little sister here, I can live a long life."

Empress Changsun's respiratory disease was not that serious originally, but she had no way to control it at that time. Moreover, she had given birth to children one after another, which made her body very weak and she could no longer resist the respiratory disease.

Just slowly recuperate in the future.

Li Shimin felt relieved and immediately ordered people to eat.

Empress Chang Sun was not so optimistic. She knew her own health very well.

Li Yin noticed it and leaned in to whisper, "Don't worry, sister-in-law. I'll tell you in detail after dinner."

When Empress Changsun heard this, she felt relieved.

Sure enough, there was something wrong, but my sister-in-law said it could be cured.

She was also afraid that something would happen to her. It wouldn’t matter if something happened to her, but she was afraid for Erlang and the children… (Historically, after Empress Changsun left, the situation of the royal family became worse.)

"It will be delicious if cooked with this bean curd." Empress Changsun was happy and her appetite improved.

"Sister, are there any good things in Tuyuhun that would make people willing to go there?" Li Shimin saw that there were always good things in Li Yin's manor, and thought of the border war, so he asked casually.

Li Yin drank some juice to clear her mouth: "Brother, there is a place in this world where all the salt grows on the surface. People can pick it up and eat it after a simple process. Moreover, the stock is quite huge, enough for all the people of the Tang Dynasty to eat for 100,000 years!"

He added: "Salt is a necessity for the people. We should not raise the price by regulation. We should improve the salt production technology, make small profits but quick turnover, and earn the same amount of money. The people can also eat salt, which will give them the strength to work. If they can work, they can make money. If they have money, they can get married and have children."

Li Shimin understood this principle. Salt was not difficult to obtain, but he had never seen a large storage volume like his sister-in-law said.

"Sister, the current refining method cannot be any cheaper."

The Tang Dynasty had no shortage of salt; what it lacked was methods to extract impurities and quickly make salt.

Today's crude salt, even if it is filtered, distilled and purified, still contains a lot of magnesium chloride. Moreover, the cost of distillation and purification is also high. People buy filtered salt, which not only contains chemical impurities, but some also have residual dirt.

Li Yin glanced at Feng Sanxi, and then everyone saw Feng Sanxi take out a piece of paper from his lapel.

"Brother, please take a look." Li Yin looked at the contents on the paper and suddenly didn't know where to start as there was too much chemical knowledge involved.

Li Shimin also looked at the paper, and then: "..."

"The first step is to dissolve the crude salt, that is, to dissolve the salt in water. The second step is to filter out the impurities that are insoluble in water, which are mostly mud and sand. The third step is to add a slightly excessive amount of barium chloride. Barium chloride is a chemical agent. To prepare barium chloride, barite and calcium chloride need to be ground into powder, and then charcoal powder is added..."

Half an hour later.

Everyone added soup for the third time.

"Sister!" Li Shimin stopped her immediately: "This is a new subject, and I think someone needs to study it systematically."

Li Yin finally finished her painful explanation and quickly replied, "Brother is right. I am currently building a college, and these experiments will be managed by the Chemistry Department of the Institute."

"College?" Another new word. My sister asked me for the official seal to buy land in order to build a college!

What kind of college needs 800 acres?

"Erlang, my sister must be talking about a private school."

"Sister-in-law is smart." Li Yin said, "It is a private school, but not completely. The academy is open to the public and anyone who is willing to learn can enroll. The school is divided into three major departments, elementary school, middle school and university, and each major department is divided into three small grades. Elementary school grades 1, 2 and 3, middle school grades 4, 5 and 6, and university grades 7, 8 and 9. Elementary school has a graduation exam, and you can only get a diploma if you pass the exam. To enter middle school, you need to take an entrance exam, and you can only start studying if you pass the exam. Those who enter university also need to take an exam. If you pass the exam, you only need to choose to study one subject, and you need to specialize in it. After graduation, you can enter the research institute."

At this point, Li Yin looked at Li Shimin and said, "Brother, the research institute has only one purpose, which is to research good things that benefit the country and the people. If there are many good things researched, you should be granted a title, but it cannot be hereditary."

Everyone at the table fell silent.

Li Shimin's breathing became increasingly rapid, but he remained calm: "Sister, where will the money for the construction come from? How can we convince the people to enroll in school?"

"Brother, technology is invested and business taxes are collected. Moreover, if businessmen want to make money, they have to learn. How can they understand those knowledge without learning?" Li Yin asked Feng Sanxi to take out many prescriptions again.

Li Shimin read them one by one, and Empress Changsun also read them. There were indeed many things they did not understand.

Sugar production method, papermaking method, tea frying method, salt purification method, ceramic production method...

"Sister-in-law!" Li Shimin was excited. With such good things, was he still afraid that the noble families wouldn't pay for it?

Those who are good at learning should be given a title! These are all good things!

Empress Changsun took a look and was extremely calm. She took the prescription from Li Shimin and gave it back to Feng Sanxi: "Sister, keep these methods. When you need them, take them out again."

"Brother, there is a salt lake in Tuyuhun. As I said, using this purification method, the cost of ten kilograms of salt is less than half a cent. If the news is released, I believe many people are willing to support the army with practical actions to capture Tuyuhun. By then, there will be no need for people to guard it, and they will not give up that piece of land on their own."

"Of course, we still have to defend it. We only need to auction the mining rights of the salt lake every five years, and the stationed troops can be self-sufficient and even have a lot of surplus... If the troops and generals are replaced every three years, I believe many soldiers are willing to spend three years to earn enough money to marry a wife."

There is another benefit that Li Yin didn't mention, which is that it can prevent generals from corruption and bribery.

As long as the local bosses don't go overboard and take some, it doesn't matter. We don't even need them to steal. We will take the initiative to give them more, and they will still take after we have given them enough. What else can you say?

When the time comes, just kneel down, stick your head out, and don't make excuses.